Well, of course the truck was warm by the time I got to the dealer so they couldn't hear it. I had a recording of the tick and the tech said it sounded like the high pressure fuel pump but said they all do it. It's bs but what can I do?
Screw it, it's under warranty. If something breaks, I'll get it fixed.

So this morning I started it. The sound started about 10 seconds into idle. It sounds like it increases with rpms but the engine drowns out the noise at 1200 rpms.
I'm thinking it's got to be something related to the exhaust.

I tried to listen to it while pressing on the accelerator. The engine ended up drowning out the sound, so i couldn't tell if it increased with rpms. What i dont understand, is the sound goes away once the truck is up to normal temperature.
The sound seems to be coming from the drivers side, down by the exhaust.

After listening more, I don't think it's the injectors. Listen to this clip and you can hear the blinker sound. Goes away once the truck is warm.
Here is a link from YouTube. It sounds like a blinker.
Watch "2018 Chevy knock" on YouTube https://youtu.be/dqqfRdke9Yk

230 miles on my new 18. Just started hearing the noise yesterday. On a cold start, it literally sounds like my blinkers are on. The sound is coming from the bottom of the engine on the drivers side. Once the engine is warmed up, the sound goes away.
I cant hear the sound from inside the cab. Only reason I heard it yesterday, is because as soon as I started the truck, I got out to run back into the house.
Exhaust leak?